This invention relates to the harnessing of the items and more particularly to the realization of efficient, low-cost, high strength harnessing devices which are easy to use.
Harnessing devices are widely used for the bundling of objects. Such devices are typically formed with a serrated strap that is fitted to an apertured head containing an internal pawl or locking tang that engages the serrations of the strap. Other harnessing devices are in the form of an apertured strap fitted to a buckle-like head, with a tongue that enters the apertures of the strap.
Harnessing devices with serrated straps have the disadvantage of being only as secure as their pawls. Where the items that are harnessed are heavy or are subjected to rough handling, the items often become accidentally released, for example, by failure of the pawls. Attempts have been made to strengthen serrated strap devices, but this has resulted in considerable complexity without achieving the desired end result of providing security against accidental release of the harnessed items. Similar objections apply to harnessing devices with buckle-like heads. In these devices, a tongue which enters the strap apertures rests against the head of the buckle near its opening and is deflected by the strap. The tongue is typically a cantilever attachment to the buckle-like head, which tends to be unduly stiff in the direction of forward thrust during harnessing, and insufficiently stiff in the direction of reverse thrust applied by the strap because of the harnessed items. In addition the tongue is exposed to external interferences that can cause an accidental release of the harnessed items.
In order to avoid and overcome many of the difficulties associated with the foregoing kinds of harnessing devices, ladder straps and associated locking tangs have been developed of the kind disclosed in U.S. Pat. No. 3,766,608, which issued Oct. 23, 1973. The ladder strap device represents a significant improvement over the serrated strap and other harnessing devices. It can accomplish substantially the same functions as a serrated strap device at a considerably lower cost. The ladder strap can be produced with a significant saving in material and can be stretched to reorient its molecular structure and strengthen its constituents without strap distortion, as would occur if an attempt were made to stretch a serrated strap.
Notwithstanding its advantages, however, the ladder strap typically includes a tail section that is inadequate in many situations to achieve desired speed and flexibility in use. For example, the commonly used tail can cause operator difficulty in insertion of the strap into the head. The tail also often provides an inadequate gripping surface for an automatic tool which is used to suitably tension the strap and then subsequently sever any excess length. The foregoing difficulties cannot be overcome by mere extension of the strap since that would result in a tail that contains too much bulk for efficient application. Such a tail would not only be difficult to handle, but it would be wasteful of material. Conversely, if the tail is made of reduced thickness as compared with the remainder of the strap, the resulting structure would have insufficient mass for efficient handling. It would also present difficulties in being grasped by tendency to move about uncontrollably because of its lack of bulk.
Accordingly, it is an object of the invention to provide for the secure harnessing of items. A related object is to achieve secure harnessing without the need for a complex harness configuration.
A further object of the invention is to provide a tail structure for a harnessing device which promotes the efficient, accurate and rapid use of the device. A related object is to provide a suitable tail structure for a harnessing device without an undue increase in bulk. Another related object is to overcome the difficulties associated with ordinary tail structures. Another object is to produce a suitable, economical tail structure. A related object is to produce a tail structure which has sufficient mass for suitable usage, while being sufficiently light in weight that it does not interfere with harnessing operations.
Another object of the invention is to reduce the material and molding requirements associated with the filling of molds and the production of harnessing devices with lengthened tail. A related object is to reduce molding and material requirements in the manufacture of ladder strap harnessing devices with elongated tails.